Grinding tool



June 10, 1941.

J. L. DONDINEAU ETAL GRINDII QG TOOL Filed July 10,1939

INV EN TORS JAMESL.DONDINEAU R0 $.WHITE I ATTORNE s Patented June 19, 1941 UNHTE STATES PATENT was Fi m

GRINDING TOOL Application July 10, 1939, Serial No. 283,682

4 Claims.

This invention relates generally to finishing tools and refers more particularly to an improved portable grinding tool.

It is one of the principal objects of this invention to provide a portable tool assembly having a ring provided with material removing means on the radially inner surface thereof for engaging a work blank adapted to be extended through the ring and, in addition, having means engageable with the peripheral surface of the ring for rotatably supporting the latter.

Another feature of the invention is to provide a tool assembly wherein the ring is provided with an annular series of gear teeth adapted to mesh with a driving toothed element and wherein an annular bearing surface is provided on each side of the series of gear teeth for adequately rotatably supporting the ring.

Another advantageous feature of the present invention consists in the provision of a compact relatively light weight portable grinding tool constructed in such a manner as to permit accurately finishing or grinding the crank pins of an engine crankshaft and having an adjustable feature rendering it possible to grind crank pins of various different diameters.

Another object of this invention resides in the provision of a grinding tool of the character set forth capable of being readily assembled on and removed from a crank pin on a crankshaft with- .out disassembling the crankshaft from the engine.

Still another feature of this invention consists in the provision of a grinding tool having a rtatable ring carrying abrasive means on the radially inner surface thereof for engagement with r provision of a grinding tool of the type set forth in the preceding paragraph wherein the ring is formed of complementary halves secured together with the crank pin therebetween and bound the radially outer surfaces of the halves fashioned to form a continuous series of spiralled gear teeth.

A still further object of this invention consists in providing a tool wherein the ring sections are formed to provide the ring with annular bearing surfaces at opposite ends of the gear teeth and wherein the ring is carried by a retainer having cooperating bearing surfaces supportedly engaging the bearing surfaces on the ring to permit free rotation of the ring relative to the retainer.

A still further feature of this invention resides in the provision of a grinding tool wherein the retainer is formed of two substantially semicircular parts pivotally connected together to permit assembly of the ring in the retainer and wherein one of the parts supports a driving worm adapted to mesh with the teeth on the periphery of the ring.

In addition to the foregoing, the present invention contemplates a grinding tool having abrasive membersi spaced equal distances circumferentially from each other on the radially inner surface of the ring and having one of the abrasive elements radially adjustable to provide for grinding the pin to predetermined dimensions.

The foregoing, as well as other objects, will be made more apparent as this description proceeds,

especially when considered in connection with the accompanying drawing, whereby:

Figure 1 is a side elevational view of a grinding tool constructed in accordance with this invention and showing the same in assembled relation with a crank pin;

Figure 2 is a sectional view taken substantially on the plane indicated by the line Z--2 of Figure 1;

Figure 3 is a sectional view taken substantially on the plane indicated by the line 3-3of Figure 2;

Figures 4, 5 and 6 are, respectively, sectional views taken substantially on the planes indicated by the lines 44, 5-5, and 68 of Figure 1;

Figure '7 is a group perspective View of the ad- .without disassembling the crankshaft from the engine. However, it will be understood as the description proceeds; that our improved grinding tool may be used for other purposes and should not be considered as limited to the specific application selected herein for the purpose of illustration.

In general, the grinding tool illustrated herein comprises a retainer Ill and an abrasive ring H having abrasive elements l2 on the radially inner surface thereof. The ring H is formed of two complementary sections or halves l3 and I4 hav-- ing rabbeted portions l5 and it at the opposite ends secured together by machine screws H to provide the continuous ring II. The arrangement is such as to permit the complementary sections or halves of the ring to be readily separated from each other and assembled together with a crank pin l8 of a suitable crankshaft is therebetween.

In the present illustrative embochment of the invention, three abrasive elements l2 are pro-- vided for engagement with the crank pin 58 to grind or finish the latter, and the elements l2 are spaced circumferentially from each other approximately 120. Upon reference to Figure 3, it will be noted that each of the elements is mounted on the ring H for sliding movement radially of the ring to provide for engaging the abrasive surfaces of the elements with crank pins of various diameters. Two of the elements are adjusted by the use of shims 2s and the other element is movable radially of the ring by means of a screw adjustment shown in Figures to '7, inclusive. The latter adjustable element is designated more particularly in the drawing by the reference character 21 and comprises a sheet metal substantially U-shaped holder 22 having the side flanges 23 slidably engaging in suitable slots 24 formed in the ring H. The base 25 of the holder is curved on a radius having the axis of the ring H as its center or, in other words, is concentric with the radially inner surface of the ring. The base 25 forms an abutment for a correspondingly curved clip 2% having the abrasive material 2'! cemented, or otherwise secured to the radially inner surface thereof and having tabs 28 at opposite ends adapted to be crimped around the adjacent ends of the holder 22.

In order to adjust the holder 22 radially of the ring, a pair of U-shaped members 29 are. arranged upon opposite sides of the ring with the flange portions 38 extending into the slots 24 and each of the flanges 38 is fashioned with tapered cam surfaces 3! adapted to engage correspondingly tapered surfaces 32 formed on the flanges 23 of the U-shaped holder 22. Upon reference to Figure 6, it will be noted that movement of the members 29 toward each other will eifect a radially inward movement of the holder 22 and associated abrasive material 27. The above adjustment of the members 29 is accomplished by means of screws 33 threaded into D- posite sides of the ring it and accessible for manipulation to effect the desired adjustment. As shown in Figure 6, movement of the members 29 toward each other by the screws 33 is accomplished against the action of suitable coil springs 34 extending through the ring I l with the opposite ends abutting the members 29. As a result, when the screws 33 are loosened, the springs E i function to separate the members 29 and permit radial outward movement of the holder 22 and associated abrasive material 21.

The remaining two abrasive elements R2 are identical in construction and each comp-rises a.

substantially U-shaped holder 35 having the flange portions slidably engaging within slots 3 5 formed in the ring and having an arcuate base portion 3? concentric with the radially inner surface of the ring. The base portion 3'5 of each abrasive element forms a seat for a clip 38 identical in construction to the clip 26 in that it carries the abrasive material 39 and is secured to the base 31 by means of the lugs 49.

The abrasive material 39 associated with each of the holders 35 is positioned radially with reference to the ring by means of the shims located between the radially outer surfaces of the base portions 37 and the adjacent surface of the ring ii. If desired, each of the holders may be provided with a pin 4| extending radially outwardly from the base 31 between the flanges of the holder and adapted to slidably engage within a bore 42 formed in the ring. These pins permit clamping the holders 35 in assembled relation with the ring by providing screws 43 having shank portions threaded into the ring and adapted to frictionally engage the pins 4|.

It will, of course, be understood that the ring ii is revoluble to effect the grinding operation on the crank pin l8 and, in the present instance, the ring is rotatably supported in the retainer Ii). Upon reference to Figure 2, it will be noted that the ring H is provided with axially spaced annular bearing surfaces t5 supportedly engaging) corresponding annular bearing surfaces 46 formed on the retainer ill. Rotation of the ring ll relative to the retainer is effected by means of a worm 4'1 rotatably supported on the retainer in mesh with spiralled teeth 48 formed on the periphery of the ring between the bearing surfaces 45. The teeth 48 are fashioned on the radially outer surface of each half of the ring in such a manner that when the two halves of the ring are secured together, the teeth on each half cooperate to form in effect a worm gear.

The worm i! is shown in Figure 3 as located within an extension or housing 49 formed on the retainer Iii and is secured to a drive shaft 58 journalled in the end walls of the housing 49. One end of the drive shaft projects a sufficient distance beyond the housing to permit the same to be engaged by a suitable source of power, such as a portable electric drill. 7

The retainer I9 is formed of two substantially semi-circular sections 5| and 52. Both sections are substantially channel-shaped in cross section and are pivotally connected together at one end thereof by means of a pin 53 for swinging movement from the closed position thereof shown in Figure 1 to an open position wherein the ring H i may be removed therefrom. In the closed position of the sections shown in Figure 1, the free ends 54 of the sections abut each other and are secured together by means of a clamp 55.

Each of the sections of the retainer is channel-shaped in cross section with the channel 56 opening inwardly to receive the gear teeth 48 on the periphery of the ring H and the free edges of the flanges of the channel are machined to form thebearing surfaces 46.

Operation Assuming that it is desired to assemble the tool previously described With the crank pin l8 on the crankshaft 19, it will be noted that the ring II is removed from the retainer II] by disengaging the clamp 55 from the free ends of the sections of the clamp. The sections of the clamp may then be swung to their open positions so as to enable the ring ll to be removed from the retainer. It will, of course, be understood that as the sections of the clamp are swung to their open positions, the worm 1 is swung out of engagement with the teeth 48 on the periphery of the ring ll.

After the ring if has been removed from the retainer, the sections of the ring are disengaged from each other by removing the fastener elements If. The two halves of the ring are then placed over the crank pin i8 and secured together with the crank pin 18 therebetween. Prior to assembling the ring H on the crank pin I8, the holders 35 are radially positioned in the manner previously described to locate the abrasive clips in positions to engage the bearing surface of the crank pin I8 and, subsequent to assembling the ring on the pin is, the abrasive element 2| is adjusted by manipulating the screws 33 to engage the abrasive material 27 on the clip 25 with the bearing surface of the crank pin 18.

After the ring has been properly assembled on the crank pin [8, the retainer is assembled over the ring and the sections of the retainer are secured in place by means of the clamp 55. The drive shaft 50 may then be engaged by the clutch not shown) of an electric drill or similar source of power to effect the rotation of the ring ll necessary to accomplish the grinding operation.

What we claim as our invention is:

1. A portable tool having a rotatable ring comprising separable sections and formed with a plurality of circumferentially spaced pairs of slots opening through the inner surface of the ring, the slots in each pair being parallel and extending perpendicular to the plane of rotation of the ring, a U-shaped member associated with each pair of slots and having the leg portions slidably engageable in the slots, and abrasive means mounted on the inner surfaces of the base portions of the U-shaped members.

2. A portable tool having a rotatable ring comprising separable sections and formed with a plurality of circumferentially spaced pairs of slots opening through the inner surface of the ring, the slots in each pair being parallel and extending perpendicular to the plane of rotation of the ring, a U-shaped member associated with each pair of slots and having the leg portions slidably engageable in the slots, abrasive means mounted on the inner surfaces of the base portions of the U-shaped members, and means accessible for manipulation from one side of the ring and having portions extending into the slots of one of said pairs for engagement with the legs of the associated U-shaped member to adjust the latter with respect to the ring.

3. A portable tool having a rotatable ring comprising separable sections and formed with a plurality of circumferentially spaced pairs of slots opening through the inner surface of the ring, the slots in each pair being parallel and extending perpendicular to the plane of rotation of the ring, a U-shaped member associated with each pair of slots and having the leg portions slidably engageable in the slots, abrasive means mounted on the inner surfaces of the base portions of the U- shaped members, a pair of U-shaped elements positioned on opposite sides of the ring in registration with each U-shaped member and having leg portions extending into the adjacent slots in the ring from opposite sides of the ring, the leg portions of the U-shaped elements being positioned in the slots radially outwardly of the leg portions on the U-shaped members, the legs of the U-shaped members having cooperating engaging inclined surfaces responsive to movement of the U-shaped elements toward each other in the direction of the axis of the ring to adjust the U-shaped members, and means for adjusting the U-shaped members.

4. A portable tool having a retainer compris ing separable sections provided with hearing surfaces cooperating in the assembled relationship of the sections to form axially spaced annular bearing surfaces, a ring insertable between the sections of the retainer in the separated positions of the latter sections and also composed of sections removably secured together to provide for assembling the ring sections with a work piece extending through the ring, said ring having a plurality of pairs of circumferentially spaced slots therethrough opening through the inner surface of the ring, the slots of each pair being parallel and extending perpendicular to the plane of rotation of the ring, a U-shaped member associated with each pair of slots and having the leg portions slidably engageable in the slots, the inner surfaces of the base portions of the U-shaped members being concentric with the axis of rotation of the ring and carrying abrasive means for engagement with the work extending through the ring, said ring having ax ally spaced bearing surfaces rotatably engaging the bearing surfaces on the retainer, and means for rotating the ring.

JAMES L. DONDINEAU. BOY S. WHITE. 

